This invention relates generally to refrigerators and, more particularly, to an apparatus and method for displaying a temperature of a refrigerator compartment.
Known refrigeration appliances typically include one or more refrigeration compartments for the storage of fresh food and for frozen food storage. Conventionally, temperature settings for fresh food compartments and freezer compartments are adjustable through manipulation of an electromechanical mechanism, such as a dial or sliding switch. Depending on a user selected position of the electromechanical mechanism or mechanisms, refrigerator controls regulate the temperature of the respective refrigerator compartments to a temperature corresponding to the temperature position. However, because with these systems there is no apparent way to determine an actual temperature of the departments, operating temperature settings are often determined by user trial and error. In addition, excessive deviation from selected temperature settings indicative of a refrigerator malfunction are difficult to detect.
The proliferation of electronic controls in appliances offer enhanced control schemes for appliances, including, for example, feedback displays to the user indicative of temperature settings. Thus, the displays provide visual confirmation of selected settings as well as confirmation that selected temperatures are being maintained. However, electronic controls can sometimes be confusing to operate, and further can mislead users to believe that the appliance is not operating properly because the system does not respond like conventional electromechanical systems. Thus, for example, indication of rapid temperature changes or apparently unstable temperature displays may cause a user to place a service call when the refrigerator is otherwise working normally. As another example, when a new temperature setting does not produce immediate change in refrigerator behavior, (as will be the case when the new temperature setting is below the actual temperature of the compartment) a user may believe that the refrigerator is not working.
It would be desirable to provide an easy to use electronic control system for a refrigerator that includes temperature displays while avoiding behavior inconsistent with conventional systems.
In an exemplary embodiment of the invention, a system for displaying a temperature of a refrigerator compartment including at least one temperature sensor is provided that emulates the function and behavior of a thermostat to control and display refrigerator compartment temperature in a simple and intuitive manner. The system includes a controller including a processor and a memory, and is operatively coupled to the temperature sensor. A human machine interface board includes a display and is coupled to the controller and configured for receiving user input of a refrigerator compartment setting. The controller is configured to accept a set temperature of the compartment, monitor an actual temperature of the compartment; and display a damped temperature value based on operating conditions of the refrigerator.
In one embodiment, the controller damps the temperature value for one of several fixed time constants depending on a mode of operation of the refrigerator and conditions in the refrigerator compartment. Alternatively, the controller calculates a damped temperature value based upon a rolling average of actual temperature and the set temperature, or upon a rolling average of actual temperature and a current display register value in the controller memory. Therefore, displayed temperature values are adjusted in a stable manner.
Moreover, the controller is configured to respond appropriately to user settings where a response is not otherwise necessary to confirm to the user that the system is operating. Thus, for example, if a temperature setting is lowered to a point above the operating temperature of the compartment, fans are energized briefly in accordance with user expectations that the adjusted setting should cause the fans to be turned on. User confusion and possible associated service calls due to a non-responsive refrigerator is therefore avoided.